"Although the revised deal brings much-needed modernization in areas such as e-commerce and intellectual property, the media spotlight on Canada has obscured a bigger problem for the region: Under the new terms, North American trade is headed off the rails and, perhaps along with it, political stability south of the border," they write.

Major problems with the deal, they write, include the elimination of expert panels for resolving government-investor disputes in most industries and ther deal's mechanism for automatically reviewing its terms on a periodic basis and 16-year automatic expiration, conditions that make it cheaper for governments to upend existing rules and threaten to exit the agreement.

"Both of these changes point to a bigger problem with the new deal: the deinstitutionalization of North American economic ties," they write.

"The certainty and centrality of Nafta to United States-Mexican relations has proved integral to aligning the two countries’ economic and strategic interests. Before Nafta, relations were far from harmonious, in part because Mexico’s interests were solidly on the side of the global south. Pointing to a history of invasions, occupations and the loss of half of its territory to the United States, Mexico long saw its northern neighbor as a threat to be contained."